This invention relates to rotary cutting tools such as routing cutters and end mills, intended to be used to machine slots and/or recesses in a workpiece.
GB 2186220 shows a routing tool in which, typically, a pair of cutter blades are mounted at diametrically opposed positions of a rotary body in flutes formed in the sides of the body, each blade having a cutting edge that extends along the flute over its radially outer edge and continues inwards and rearwards over end portions of the blades that project forwards from the axial end of the tool body. In a routing operation in which the cutter moves along the workpiece in a direction perpendicular to its rotary axis, only the radially outer cutting edge is employed. The inward and rearward continuation of the cutting edge at the end of the tool body is necessary to permit the tool to be given an axial feed movement into the workpiece at the same time as it moves along the workpiece. During such a ramping movement the end portions of the blades then act to remove a core of material that is left projecting above the instantaneous depth reached by the outer part of the cutting edge.
For this reason, routing cutters and like rotary tools which are required to perform a ramping motion have relatively large and complex cutter blades and the cost of production is consequently relatively high even if, as in the example already mentioned, the cutter blades are formed separately from the body of the tool.